# Patent

## Title
Zoom lens and imaging apparatus

## Abstract

A zoom lens is constituted by, in order from the object side to the image side: a positive first lens group which his fixed when changing magnification; at least two moving lens groups that move when changing magnification; and a positive final lens group which is fixed when changing magnification. The first lens group is constituted by, in order from the object side to the image side: a negative 1a lens group which is fixed during focusing operations, a positive 1b lens group which moves during focusing operations, and a positive 1c lens group which is fixed during focusing operations. The 1a lens group includes at least one negative lens that satisfies predetermined conditional formulae.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2015-185015 filed on Sep. 18, 2015. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.
BACKGROUND
The present disclosure is related to a zoom lens which can be utilized in electronic cameras such as a digital camera, a video camera, a broadcast camera, a cinematic camera, a surveillance camera, etc., and to an imaging apparatus equipped with this zoom lens.
The zoom lenses disclosed in Japanese Unexamined Patent Publication Nos. 2013-221999 and 2012-013817 are proposed as zoom lenses to be employed in electronic cameras such as a digital camera, a video camera, a broadcast camera, a cinematic camera, a surveillance camera, etc.
Conventional broadcast cameras perform imaging according to the HD (High Definition) standard, and the maximum resolution thereof had been Full HD (1920×1080 pixels). Recently, there are many cameras which are compatible with the 4K standard (3840×2160 pixels, for example) which has approximately four times the number of pixels of Full HD, and imaging employing such cameras is increasing. Further, there are cameras which are compatible with the Super High Vision standard, which has an even greater number of pixels than 4K. High performance lenses are desired for these high pixel number cameras.
However, the lenses disclosed in Japanese Unexamined Patent Publication No. 2013-221999 include many having comparatively wide angles of view, but it cannot be said that these lenses sufficiently correct aberrations. In addition, the lenses disclosed in Japanese Unexamined Patent Publication No. 2012-013817 have sufficiently wide angles of view, but it cannot be said that the lenses are sufficiently miniaturized with respect to image size.
The present disclosure has been developed in view of the foregoing circumstances. The present disclosure provides a high performance zoom lens which is compact, has a wide angle of view, and favorably corrects various aberrations. The present disclosure also provides an imaging apparatus equipped with this zoom lens.
A zoom lens of the present disclosure consists of, in order from the object side to the image side:
a first lens group having a positive refractive power, which is fixed when changing magnification;
at least two moving lens groups that move to change the distance among adjacent lens groups in the direction of the optical axis when changing magnification; and
a final lens group having a positive refractive power, which is fixed when changing magnification;
the first lens group consisting of, in order from the object side to the image side: a 1a lens group having a negative refractive power which is fixed during focusing operations; a 1b lens group having a positive refractive power which moves during focusing operations; and a 1c lens group having a positive refractive power which is fixed during focusing operations; and
the 1a lens group including at least one negative lens that satisfies Conditional Formulae (1), (2), and (3) below

62<νd1an  (1)

0.65<θgF1an+0.001625·νd1an<0.7  (2)

3<f1an/f1a<7  (3)

wherein νd1an is the Abbe's number with respect to the d line of the negative lens within the 1a lens group, θgF1an is the partial dispersion of the negative lens within the 1a lens group, f1an is the focal length with respect to the d line of the negative lens within the 1a lens group, and f1a is the focal length with respect to the d line of the 1a lens group.
Note that it is more preferable for any one or any combination of Conditional Formulae (1-1), (2-1), and (3-1) below to be satisfied in addition to Conditional Formulae (1), (2), and (3).

70<νd1an<100  (1-1)

0.66<θgF1an+0.001625·νd1an<0.69  (2-1)

4<f1an/f1a<6  (3-1)

In addition, it is preferable for Conditional Formula (4) below to be satisfied. Note that it is more preferable for Conditional Formula (4-1) below to be satisfied.

8<f1c/fw<24  (4)

9<f1c/fw<21  (4-1)

    
    
        wherein f1c is the focal length with respect to the d line of the 1c lens group, and fw is the focal length with respect to the d line of the entire lens system at the wide angle end.
    
    


In addition, it is preferable for the 1a lens group to satisfy Conditional Formulae (5), (6), and (7) below. Note that it is more preferable for any one or any combination of Conditional Formulae (5-1), (6-1), and (7-1) below to be satisfied in addition to Conditional Formulae (5), (6), and (7).

νd1ap<40  (5)

20<νd1ap<39  (5-1)

0.62<θgF1ap+0.001625·νd1ap<0.67  (6)

0.63<θgF1ap+0.001625·νd1ap<0.66  (6-1)

0.4<f1ap/f1<2  (7)

0.5<f1ap/f1<1.5  (7-1)

wherein νd1ap is the Abbe's number with respect to the d line of a positive lens within the 1a lens group, θgF1ap is the partial dispersion of the positive lens within the 1a lens group, f1ap is the focal length with respect to the d line of the positive lens within the 1a lens group, and f1 is the focal length with respect to the d line of the first lens group.
In addition, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power. Alternatively, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a negative refractive power, and a third lens group having a negative refractive power.
As a further alternative, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a negative refractive power. In this case, it is preferable for Conditional Formula (8) below to be satisfied. Note that it is more preferable for Conditional Formula (8-1) below to be satisfied.

1.7<DL3/DL2<20  (8)

2.1<DL3/DL2<17  (8-1)

wherein DL3 is the range of movement of the third lens group, and DL2 is the range of movement of the second lens group.
Here, the “range of movement” refers to the amount of displacement from the position most toward object side to the position most toward the image side of each lens group when changing magnification from the wide angle end to the telephoto end.
In addition, in the case that the moving lens groups consist of three lens groups which are positive, negative, and negative as described above, it is more preferable for Conditional Formula (9) below to be satisfied. Note that it is more preferable for Conditional Formula (9-1) below to be satisfied.

0.4<f3/f4<0.8  (9)

0.5<f3/f4<0.7  (9-1)

wherein f3 is the focal length with respect to the d line of the third lens group, and f4 is the focal length with respect to the d line of the fourth lens group.
In addition, in the case that the moving lens groups consist of three lens groups which are positive, negative, and negative as described above, it is preferable for the third lens group to have two cemented lenses, for at least one of the cemented lenses to consist of a positive lens and a negative lens, and for Conditional Formula (10) below to be satisfied. In this case, it is preferable for the cemented lens provided most toward the image side within the third lens group to satisfy Conditional Formula (10). Note that it is more preferable for Conditional Formula (10-1) to be satisfied.

0<νd3p−νd3n<10  (10)

4<νd3p−νd3n<10  (10-1)

wherein νd3p is the Abbe's number with respect to the d line of the positive lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group, and νd3p is the Abbe's number with respect to the d line of the negative lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group.
An imaging apparatus of the present disclosure is equipped with the zoom lens of the present disclosure described above.
Note that the above expression “consists of” means that lenses that practically have no power, optical elements other than lenses such as a stop, a mask, a cover glass, and filters, and mechanical components such as lens flanges, a lens barrel, an imaging element, a camera shake correcting mechanism, etc. may be included, in addition to the constituent elements listed above.
In addition, the surface shapes and the signs of the refractive powers of the lenses described above are considered in the paraxial region in cases that aspherical surfaces are included.
The zoom lens of the present disclosure consists of, in order from the object side to the image side: a first lens group having a positive refractive power, which is fixed when changing magnification; at least two moving lens groups that move to change the distance among adjacent lens groups in the direction of the optical axis when changing magnification; and a final lens group having a positive refractive power, which is fixed when changing magnification. The first lens group consists of, in order from the object side to the image side: a 1a lens group having a negative refractive power which is fixed during focusing operations; a 1b lens group having a positive refractive power which moves during focusing operations; and a 1c lens group having a positive refractive power which is fixed during focusing operations. The 1a lens group includes at least one negative lens that satisfies Conditional Formulae (1), (2), and (3) below. Therefore, it is possible to realize a high performance zoom lens which is compact, has a wide angle of view, and favorably corrects various aberrations.

62<νd1an  (1)

0.65<θgF1an+0.001625·νd1an<0.7  (2)

3<f1an/f1a<7  (3)

In addition, the imaging apparatus of the present disclosure is equipped with the zoom lens of the present disclosure. Therefore, the imaging apparatus of the present disclosure can be miniaturized, and is capable of obtaining wide angle images having high image quality.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to an embodiment of the present disclosure (common with a zoom lens of Example 1).
FIG. 2 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 2 of the present disclosure.
FIG. 3 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 3 of the present disclosure.
FIG. 4 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 4 of the present disclosure.
FIG. 5 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 5 of the present disclosure.
FIG. 6 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 6 of the present disclosure.
FIG. 7 is a collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to Example 7 of the present disclosure.
FIG. 8 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 1.
FIG. 9 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 2.
FIG. 10 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 3.
FIG. 11 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 4.
FIG. 12 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 4.
FIG. 13 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 6.
FIG. 14 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 7.
FIG. 15 is a diagram that schematically illustrates an imaging apparatus according to an embodiment of the present disclosure.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. FIG. 1 is collection of cross sectional diagrams that illustrate the lens configuration of a zoom lens according to an embodiment of the present disclosure. The example of the configuration illustrated in FIG. 1 corresponds to the configuration of a zoom lens of Example 1 to be described later. In FIG. 1, the left side is the object side, and the right side is the image side. Note that the aperture stop St illustrated in FIG. 1 does not necessarily represent the size or shape thereof, but merely indicates the position of the aperture stop St along an optical axis Z. In addition, FIG. 1 also illustrates the movement trajectory of each lens group when changing magnification form the wide angle end to the telephoto end, as well as light beams at various image heights (an axial light beam wa, a light beam wb at an intermediate angle of view, and a light beam we at a maximum angle of view).
This zoom lens of the present embodiment is constituted by, in order from the object side to the image side, a first lens group G1 having a positive refractive power, which is fixed when changing magnification; at least two moving lens groups that move such that the distances in the direction of the optical axis among adjacent lens groups change when changing magnification, and a final lens group having a positive refractive power, which is fixed when changing magnification.
By setting the refractive power of the lens group most toward the object side to be positive, it becomes possible to shorten the total length of the entire lens system, which is advantageous from the viewpoint of miniaturization. In addition, the first lens group G1, which is provided most toward the object side, and the final lens group, which is provided most toward the image side, are fixed when changing magnification. This configuration provides the advantageous effect that the total length of the entire lens system does not change when changing magnification.
When this zoom lens is applied to an imaging apparatus, it is preferable for a cover glass, a prism, and various filters such as an infrared cutoff filter and a low pass filter to be provided between the optical system and an image formation plane Sim. Therefore, FIG. 1 illustrates an example in which parallel plate shaped optical members PP1 and PP2 that presume the presence of such components are provided between the lens system and the image formation plane Sim.
The first lens group G1 is constituted by, in order from the object side to the image side: a 1a lens group G1a having a negative refractive power which is fixed during focusing operations; a 1b lens group G1b having a positive refractive power which moves during focusing operations; and a 1c lens group G1c having a positive refractive power which is fixed during focusing operations. Adopting such a configuration enables changes in the angle of view during focusing operations to be suppressed.
Further, the 1a lens group G1a includes at least one negative lens that satisfies Conditional Formulae (1), (2), and (3) below. Satisfying Conditional Formula (1) is advantageous from the viewpoints of correcting lateral chromatic aberration at the wide angle side and correcting longitudinal chromatic aberration at the telephoto side. Second order spectra can be favorably corrected, by Conditional Formula (2) being satisfied in addition to Conditional Formula (1). Conditional Formula (3) being satisfied enables an appropriate amount of refractive power necessary to correct chromatic aberrations to be obtained. Therefore, chromatic aberrations can be favorably corrected. Note that more favorable properties can be obtained by any one or any combination of Conditional Formulae (1-1), (2-1), and (3-1) below being satisfied in addition to Conditional Formulae (1), (2), and (3).

62<νd1an  (1)

70<νd1an<100  (1-1)

0.65<θgF1an+0.001625·νd1an<0.7  (2)

0.66<θgF1an+0.001625·νd1an<0.69  (2-1)

3<f1an/f1a<7  (3)

4<f1an/f1a<6  (3-1)

wherein νd1an is the Abbe's number with respect to the d line of the negative lens within the 1a lens group, θgF1an is the partial dispersion of the negative lens within the 1a lens group, f1an is the focal length with respect to the d line of the negative lens within the 1a lens group, and f1a is the focal length with respect to the d line of the 1a lens group.
In addition, in the zoom lens of the present embodiment, it is preferable for Conditional Formula (4) below to be satisfied. By configuring the zoom lens such that the value of f1c/fw is not less than or equal to the lower limit defined in Conditional Formula (4), the refractive power of the 1c lens group G1c can be prevented from becoming excessively strong. Such a configuration is advantageous from the viewpoint of correcting spherical aberration, particularly at the telephoto side. By configuring the zoom lens such that the value of f1c/fw is not greater than or equal to the lower limit defined in Conditional Formula (4), the angles of light rays that exit the 1c lens group G1c can be prevented from becoming excessively close to parallel with respect to the optical axis. Such a configuration is advantageous from the viewpoints of suppressing an increase in the diameter of the second lens group G2, which is a moving lens group, and miniaturization. Note that more favorable properties can be obtained if Conditional Formula (4-1) below is satisfied.

8<f1c/fw<24  (4)

9<f1c/fw<21  (4-1)

wherein f1c is the focal length with respect to the d line of the 1c lens group, and fw is the focal length with respect to the d line of the entire lens system at the wide angle end.
In addition, it is preferable for the 1a lens group G1a to satisfy Conditional Formulae (5), (6), and (7) below. Satisfying Conditional Formula (5) is advantageous from the viewpoints of correcting lateral chromatic aberration at the wide angle side and correcting longitudinal chromatic aberration at the telephoto side. Second order spectra can be favorably corrected, by Conditional Formula (6) being satisfied in addition to Conditional Formula (5). Conditional Formula (7) being satisfied enables an appropriate amount of refractive power necessary to correct chromatic aberrations to be obtained. Therefore, chromatic aberrations can be favorably corrected. In addition, a configuration in which Conditional Formula (7) is satisfied is also advantageous from the viewpoints of correcting spherical aberration, field curvature, and distortion. Note that more favorable properties can be obtained by any one or any combination of Conditional Formulae (5-1), (6-1), and (7-1) below being satisfied in addition to Conditional Formulae (5), (6), and (7).

νd1ap<40  (5)

20<νd1ap<39  (5-1)

0.62<θgF1ap+0.001625·νd1ap<0.67  (6)

0.63<θgF1ap+0.001625·νd1ap<0.66  (6-1)

0.4<f1ap/f1<2  (7)

0.5<f1ap/f1<1.5  (7-1)

wherein νd1ap is the Abbe's number with respect to the d line of the positive lens within the 1a lens group, θgF1ap is the partial dispersion of the positive lens within the 1a lens group, f1ap is the focal length with respect to the d line of the positive lens within the 1a lens group, and f1 is the focal length with respect to the d line of the first lens group.
In addition, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power (corresponding to Examples 1 and 2 to be described later). Having three moving lens groups in this manner is advantageous from the viewpoint of suppressing fluctuations in spherical aberration and field curvature during zooming operations, compared to a case in which two moving lens groups are provided. In addition, axial light rays are reflected upward between the second lens group having a negative refractive power and the third lens group having a positive refractive power, generating spherical aberration. Changing the distance between the second lens group and the third lens group at each focal length is advantageous from the viewpoint of correcting spherical aberration in particular.
Alternatively, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a negative refractive power, and a third lens group having a negative refractive power (corresponding to Example 3 to be described later). Adopting this configuration facilitates increasing the zoom ratio, and is also advantageous from the viewpoint of lengthening back focus.
As a further alternative, the at least two moving lens groups may consist of, in order from the object side to the image side, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a negative refractive power (corresponding to Examples 4 through 7 to be described later). Having three moving lens groups in this manner is advantageous from the viewpoint of suppressing fluctuations in spherical aberration and field curvature during zooming operations, compared to a case in which two moving lens groups are provided. In addition, arranging the refractive powers of the three moving lens groups to be positive, negative, and negative in order from the object side to the image side, and distributing positive refractive power between the first lens group G1 and the second lens group G2 is advantageous from the viewpoint of miniaturization of the first lens group G1.
In addition, in the case that the moving lens groups consist of three lens groups, which are positive, negative, and negative as described above, it is more preferable for Conditional Formula (8) below to be satisfied. Configuring the zoom lens such that the value of DL3/DL2 is not less than or equal to the lower limit defined in Conditional Formula (8) is advantageous from the viewpoint of miniaturization of the first lens group G1. In addition, configuring the zoom lens such that the value of DL3/DL2 is not greater than or equal to the upper limit defined in Conditional Formula (8) is advantageous from the viewpoint of suppressing fluctuations in aberrations during zooming operations. Note that more favorable properties can be obtained if Conditional Formula (8-1) below is satisfied.

1.7<DL3/DL2<20  (8)

2.1<DL3/DL2<17  (8-1)

wherein DL3 is the range of movement of the third lens group, and DL2 is the range of movement of the second lens group.
In addition, in the case that the moving lens groups consist of three lens groups, which are positive, negative, and negative as described above, it is more preferable for Conditional Formula (9) to be satisfied. By configuring the zoom lens such that the value of f3/f4 is not less than or equal to the lower limit defined in Conditional Formula (9), the refractive power of the third lens group G3 can be prevented from becoming excessively strong. Such a configuration is advantageous from the viewpoint of suppressing fluctuations in aberrations during zooming operations. By configuring the zoom lens such that the value of f3/f4 is not greater than or equal to the upper limit defined in Conditional Formula (9), the refractive power of the third lens group G3 can be prevented from becoming excessively weak. Such a configuration is advantageous from the viewpoint of miniaturization. Note that more favorable properties can be obtained if Conditional Formula (9-1) below is satisfied.

0.4<f3/f4<0.8  (9)

0.5<f3/f4<0.7  (9-1)

wherein f3 is the focal length with respect to the d line of the third lens group, and f4 is the focal length with respect to the d line of the fourth lens group.
In addition, in the case that the moving lens groups consist of three lens groups, which are positive, negative, and negative as described above, it is more preferable for the third lens group G3 to have two cemented lenses, for at least one of the cemented lenses to consist of a positive lens and a negative lens, and for Conditional Formula (10) below to be satisfied. Lateral chromatic aberration can be favorably corrected, by Conditional Formula (10) being satisfied. In this case, if the cemented lens provided most toward the image side within the third lens group G3 satisfies Conditional Formula (10), such a configuration is advantageous from the viewpoint of achieving a balance between longitudinal chromatic aberration and lateral chromatic aberration. Further, more favorable properties can be obtained if Conditional Formula (10-1) is satisfied.

0<νd3p−νd3n<10  (10)

4<νd3p−νd3n<10  (10-1)

wherein νd3p is the Abbe's number with respect to the d line of the positive lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group, and νd3n is the Abbe's number with respect to the d line of the negative lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group.
In addition, FIG. 1 illustrates an example in which the optical members PP1 and PP2 are provided between the lens system and the image formation plane Sim. Note that various filters such as a low pass filter and a filter that cuts off specific wavelength bands may be provided among the lenses instead of being provided between the lens system and the image formation plane Sim. As a further alternative, coatings that exhibit the same effects as these filters may be administered on the lens surfaces of the lenses.
Next, examples of numerical values of the zoom lens of the present disclosure will be described.
First, a zoom lens of Example 1 will be described. FIG. 1 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 1. Note that in FIG. 1 and FIGS. 2 through 7 that correspond to Examples 2 through 7 to be described later, the left side is the object side and the right side is the image side. Note that the aperture stops St illustrated in FIGS. 1 through 7 do not necessarily represent the sizes and shapes thereof, but only the positions thereof along the optical axis Z. In addition, FIG. 1 illustrates the movement trajectory of each lens group when changing magnification from the wide angle end to the telephoto end, as well as light beams at various image heights (an axial light beam wa, a light beam wb at an intermediate angle of view, and a light beam we at a maximum angle of view).
The zoom lens of Example 1 is constituted by, in order from the object side to the image side, the first lens group G1 having a positive refractive power as a whole constituted by twelve lenses, which are lenses L1a through L1l, a second lens group G2 having a negative refractive power as a whole constituted by two lenses, which are lenses L2a and L2b, a third lens group G3 having a positive refractive power as a whole constituted by two lenses, which are lenses L3a and L3b, a fourth lens group G4 having a negative refractive power as a whole constituted by two lenses, which are lenses L4a and L4b, and a fifth lens group G5 (final lens group) having a positive refractive power as a whole constituted by eleven lenses, which are lenses L5a through L5k.
Note that the first lens group G1 is constituted by a 1a lens group G1a constituted by five lenses, which are lenses L1a through L1e, a 1b lens group G1b constituted by three lenses, which are lenses L1f through L1h, and a 1c lens group G1c constituted by four lenses, which are lenses L1i through L1l.
Basic lens data are shown in Table 1, data related to various items are shown in Table 2, data related to variable distances among surfaces are shown in Table 3, and data related to aspherical surface coefficients are shown in Table 4 for the zoom lens of Example 1. The meanings of the symbols in the tables will be described for Example 1 as an example, but the meanings are basically the same for Examples 2 through 7 as well.
In the lens data of Table 1, surface numbers that sequentially increase with the surface of the constituent element most toward the object side being designated as 1 are listed in the column Surface Number; the radii of curvature of each surface are listed in the column Radius of Curvature; and distances along the optical axis Z between each surface and a surface adjacent thereto are listed in the column Distance. In addition, the refractive indices with respect to the d line (wavelength: 587.6 nm) of each constituent element are listed in the column nd; the Abbe's numbers with respect to the d line (wavelength: 587.6 nm) of each constituent element are listed in the column νd; and the partial dispersion ratios of each optical component are shown in the column θgF.
Note that the partial dispersion ratio θgF is represented by the formula below.

θgF=(ng−nF)/(nF−nC)

wherein ng is the refractive index with respect to the g line, nF is the refractive index with respect to the F line, and nC is the refractive index with respect to the C line.
Here, the signs of the radii of curvature are positive in cases that the surface shape is convex toward the object side, and negative in cases that the surface shape is convex toward the image side. Table 1 also shows data regarding the aperture stop St and the optical members PP1 and PP2. Text reading “(Stop)” is indicated along with a surface number in the column of the surface number at the surface corresponding to the aperture stop. In addition, in Table 1, “DD [surface number]” is shown in each of the rows of distances for distances that change when changing magnification. Numerical values corresponding to the “DD [surface number]” are shown in Table 3.
The values of the zoom magnification rate, the focal length f′ of the entire lens system, the F value F No., and the full angle of view 2ω are shown as data related to various items in Table 2.
In the basic lens data, the data related to various items, and data related to variable distances among surfaces, degrees are used as the units for angles and mm are used as the units for lengths. However, it is possible for optical systems to be proportionately enlarged or proportionately reduced and utilized. Therefore, other appropriate units may be used.
In the lens data of Table 1, the symbol “*” is appended to the surface numbers of aspherical surfaces, and numerical values that represent the paraxial radii of curvature are shown as the radii of curvature of the aspherical surfaces. The data related to aspherical surface coefficients of Table 4 show the surface numbers of the aspherical surfaces and the aspherical surface coefficients related to the aspherical surfaces. The aspherical surface coefficients are the values of coefficients KA and Am (m=3, . . . , 20) within an aspherical surface formula represented by the formula below.

Zd=C·h2/{1+(1−KA·C2·h2)1/2}+ΣAm·hm 

wherein Zd is the depth of the aspherical surface (the length of a normal line from a point on the aspherical surface at a height h to a plane perpendicular to the optical axis in contact with the peak of the aspherical surface), h is height (the distance from the optical axis), C is the inverse of the paraxial radius of curvature, and KA and Am (m=3, . . . , 20) are aspherical surface coefficients.







TABLE 1







Example 1: Lens Data












Surface
Radius of






Number
Curvature
Distance
nd
νd
θgF















*1
666.7067
4.999
1.69680
55.53
0.5434


2
42.4199
23.600





*3
83.8461
3.200
1.72916
54.68
0.5445


4
49.3379
12.541





5
−553.4405
2.499
1.81600
46.62
0.5568


6
88.3515
15.367





7
−52.6801
3.094
1.49700
81.54
0.5375


8
−108.0198
1.995





9
226.4698
12.157
1.72047
34.71
0.5835


10
−99.1347
DD[10]





11
−149.3085
7.256
1.51633
64.14
0.5353


12
−93.5859
0.363





13
−7104.0081
14.003
1.59522
67.73
0.5443


14
−62.9012
3.600
1.91082
35.25
0.5822


15
−135.1302
DD[15]





16
1193.9484
3.501
1.88300
40.76
0.5668


17
83.8187
17.021
1.49700
81.54
0.5375


18
−127.1770
3.968





19
1180.8540
11.992
1.43875
94.66
0.5340


20
−79.9379
0.151





21
85.7465
3.599
1.49700
81.54
0.5375


22
111.3952
DD[22]





*23
50.2493
3.884
1.49700
81.54
0.5375


24
28.4481
14.609





25
−58.5695
1.299
1.61800
63.33
0.5441


26
61.1172
DD[26]





27
67.7627
1.310
1.80518
25.42
0.6162


28
37.2224
6.501
1.80610
33.27
0.5885


29
−396.7845
DD[29]





30
−61.5498
1.299
1.69100
54.82
0.5450


31
53.0018
4.210
1.63980
34.47
0.5923


32
−167.4243
DD[32]





33 (stop)
∞
2.000





34
142.9883
8.001
1.60311
60.64
0.5415


35
−117.7276
0.149





36
68.9537
7.959
1.80518
25.43
0.6103


37
−49.4062
1.209
1.80440
39.59
0.5730


38
390.6552
0.149





39
49.1485
7.051
1.59282
68.62
0.5441


40
−53.8291
1.400
1.84661
23.88
0.6207


41
47.3419
16.211





42
105.2124
5.070
1.80518
25.43
0.6103


43
−60.3180
0.904





44
45.6794
7.426
1.55032
75.51
0.5402


45
−50.7839
1.199
1.91082
35.25
0.5822


46
28.4405
1.220





47
37.4111
7.699
1.49700
81.54
0.5375


48
−27.9187
1.199
1.90043
37.37
0.5772


49
96.6806
0.805





50
59.3486
12.888
1.51823
58.90
0.5457


51
−34.0966
3.000





52
∞
1.400
1.51633
64.14
0.5353


53
∞
1.000





54
∞
3.760
1.51633
64.14
0.5353


55
∞
45.573
















TABLE 2







Example 1: Items (d line)











Wide Angle
Intermediate
Telephoto















Zoom Ratio
1.00
1.90
2.94



f′
12.13
23.04
35.66



FNo.
2.86
2.86
2.86



2ω (°)
101.8
62.4
43.0
















TABLE 3







Example 1: Zoom Distances











Wide Angle
Intermediate
Telephoto















DD[10]
1.439
1.439
1.439



DD[15]
7.290
7.290
7.290



DD[22]
1.968
54.830
83.418



DD[26]
3.052
4.229
4.577



DD[29]
79.508
25.750
3.536



DD[32]
8.982
8.701
1.979
















TABLE 4







Example 1: Aspherical Surface Coefficients









Surface Number











1
3
23





KA
 1.00000000E+00
1.00000000E+00
 1.00000000E+00


A3
−5.27239766E−06
6.29734828E−06
−1.02139544E−06


A4
 3.50795901E−06
−3.96037301E−06 
 1.13384984E−06


A5
−3.31085888E−08
6.51792604E−08
−5.77866089E−09


A6
−8.65590906E−10
−1.78438616E−09 
 1.19690007E−09


A7
 8.96281657E−13
−1.06599620E−11 
−2.52900213E−12


A8
 6.71083682E−13
2.11166652E−12
−3.55333229E−12


A9
−1.67241250E−15
−1.66643726E−15 
 4.37917994E−14


A10
−2.10642107E−16
−1.44494083E−15 
 9.99412214E−15


A11
 1.01537021E−19
2.07790991E−18
−7.96624653E−17


A12
 3.16964879E−20
4.00891028E−19
−1.19231165E−17


A13
 1.10649585E−22
2.11749378E−21
−1.29911119E−19


A14
 1.18662148E−24
4.67636173E−23
−8.41736339E−22


A15
−4.61902259E−27
6.26397491E−25
 3.64613783E−22


A16
−3.92782988E−28
−3.25965240E−26 
 1.68230089E−23


A17
−1.02019299E−29
−1.42576341E−27 
 4.97991649E−25


A18
−1.68302447E−31
−3.64160733E−29 
−2.56668981E−26


A19
−9.33535346E−34
−3.92860440E−31 
−1.20399023E−27


A20
 7.45653530E−35
3.69390396E−32
 2.69830848E−29









FIG. 8 is a collection of diagrams that illustrate aberrations of the zoom lens of Example 1. In the upper portion of FIG. 8, diagrams that illustrate spherical aberration, astigmatism, and lateral chromatic aberration of the zoom lens of Example 1 at the wide angle end are illustrated in this order from the left side of the drawing sheet. In the middle portion of FIG. 8, diagrams that illustrate spherical aberration, astigmatism, and lateral chromatic aberration of the zoom lens of Example 1 at an intermediate position are illustrated in this order from the left side of the drawing sheet. In the lower portion of FIG. 8, diagrams that illustrate spherical aberration, astigmatism, and lateral chromatic aberration of the zoom lens of Example 1 at the telephoto end are illustrated in this order from the left side of the drawing sheet. The diagrams that illustrate aberration are for a state in which the object distance is infinity. The diagrams that illustrate spherical aberration, astigmatism, and distortion show aberrations with the d line (wavelength: 587.6 nm) as a reference wavelength. The diagrams that illustrate spherical aberration show aberrations related to the d line (wavelength: 587.6 nm), the C line (wavelength: 656.3 nm), and the g line (wavelength: 435.8 nm) indicated by solid lines, long broken lines, and short broken lines, respectively. In the diagrams that illustrate astigmatism, aberrations in the sagittal direction and aberrations in the tangential direction are indicated by solid lines and short broken lines, respectively. In the diagrams that illustrate lateral chromatic aberration, aberrations related to the C line (wavelength: 656.3 nm) and the g line (wavelength: 435.8 nm) are indicated by long broken lines, and short broken lines, respectively. In the diagram that illustrates spherical aberration, “FNo.” denotes the F number. In the other diagrams that illustrate the aberrations, ω denotes half angles of view.
Next, a zoom lens of Example 2 will be described. FIG. 2 is collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 2. The zoom lens of Example 2 has the same number of lenses and the same lens configuration as the zoom lens of Example 1. Basic lens data are shown in Table 5, data related to various items are shown in Table 6, data related to variable distances among surfaces are shown in Table 7, and data related to aspherical surface coefficients are shown in Table 8 for the zoom lens of Example 2. In addition, FIG. 9 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 2.







TABLE 5







Example 2: Lens Data












Surface
Radius of






Number
Curvature
Distance
nd
νd
θgF















*1
666.6699
5.000
1.72916
54.68
0.5445


2
43.0807
23.978





*3
84.1784
2.799
1.72916
54.68
0.5445


4
50.0788
12.612





5
−479.4171
2.401
1.85150
40.78
0.5696


6
89.2174
15.528





7
−58.8858
2.726
1.55032
75.50
0.5400


8
−108.3907
2.900





9
237.4766
13.327
1.73800
32.26
0.5900


10
−103.6730
DD[10]





11
−164.3685
7.146
1.71300
53.87
0.5459


12
−101.3456
2.139





13
401.6455
14.020
1.59522
67.73
0.5443


14
−68.7618
3.599
1.91082
35.25
0.5822


15
−204.0821
DD[15]





16
1444.3856
3.457
1.88300
40.76
0.5668


17
86.7204
17.020
1.49700
81.54
0.5375


18
−113.2017
0.151





19
−2226.5399
11.903
1.43875
94.66
0.5340


20
−81.0370
0.149





21
98.1139
4.531
1.49700
81.54
0.5375


22
124.8710
DD[22]





*23
49.9998
3.292
1.49700
81.54
0.5375


24
28.9842
11.912





25
−60.7156
1.300
1.61800
63.33
0.5441


26
56.5813
DD[26]





27
64.3961
1.309
1.80518
25.42
0.6162


28
38.0624
6.500
1.80610
33.27
0.5885


29
−562.7136
DD[29]





30
−66.4273
1.301
1.61336
58.51
0.5458


31
45.5050
4.739
1.58144
40.75
0.5776


32
−203.3307
DD[32]





33 (stop)
∞
2.180





34
163.0118
5.453
1.60311
60.64
0.5415


35
−139.3873
0.151





36
79.1993
9.736
1.80518
25.43
0.6103


37
−45.2566
1.215
1.80440
39.59
0.5730


38
465.5491
0.150





39
48.2434
6.999
1.59282
68.62
0.5441


40
−47.7115
1.399
1.80518
25.46
0.6157


41
49.8832
16.161





42
103.4895
4.866
1.80518
25.43
0.6103


43
−60.3289
1.441





44
49.3187
6.024
1.55032
75.50
0.5400


45
−51.2447
1.201
1.91082
35.25
0.5822


46
28.8975
1.729





47
35.6674
8.397
1.49700
81.54
0.5375


48
−28.4245
1.199
1.90043
37.37
0.5772


49
102.6346
0.275





50
61.7065
12.355
1.53119
57.24
0.5488


51
−35.3650
3.000





52
∞
1.400
1.51633
64.14
0.5353


53
∞
1.000





54
∞
3.760
1.51633
64.14
0.5353


55
∞
47.179
















TABLE 6







Example 2: Items (d line)











Wide Angle
Intermediate
Telephoto















Zoom Ratio
1.00
1.90
2.94



f′
12.11
23.00
35.60



FNo.
2.86
2.86
2.86



2ω (°)
101.8
62.6
43.2
















TABLE 7







Example 2: Zoom Distances











Wide Angle
Intermediate
Telephoto















DD[10]
1.505
1.505
1.505



DD[15]
8.947
8.947
8.947



DD[22]
1.989
55.822
84.813



DD[26]
3.011
4.099
4.444



DD[29]
81.137
25.423
3.588



DD[32]
9.114
9.906
2.407
















TABLE 8







Example 2: Aspherical Surface Coefficients









Surface Number











1
3
23





KA
 1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−2.09060536E−06
5.14922043E−06
−7.33969487E−07 


A4
 3.30103959E−06
−3.94953394E−06 
9.82730601E−07


A5
−2.89916888E−08
6.66019536E−08
1.75633828E−09


A6
−8.85483471E−10
−1.72823122E−09 
8.44451809E−10


A7
 5.77451892E−13
−1.11118173E−11 
−3.33419653E−12 


A8
 6.68477203E−13
2.10761387E−12
−3.44720369E−12 


A9
−1.64782542E−15
−1.68616929E−15 
4.60544537E−14


A10
−2.10265861E−16
−1.43804417E−15 
9.99108937E−15


A11
 1.09065119E−19
1.94468185E−18
−6.83180212E−17 


A12
 3.20257753E−20
4.10997602E−19
−1.20063252E−17 


A13
 1.09401867E−22
1.97640618E−21
−1.05376576E−19 


A14
 1.14574778E−24
5.59751876E−23
−7.81212127E−22 


A15
−6.40526915E−27
3.93315141E−25
3.66816369E−22


A16
−3.68734250E−28
−3.80233095E−26 
1.15877676E−23


A17
−1.05995148E−29
−1.45288994E−27 
4.35267115E−25


A18
−1.71933930E−31
−3.78730726E−29 
−2.34133792E−26 


A19
−9.81123822E−34
−3.08108475E−31 
−1.31277037E−27 


A20
 7.78816919E−35
3.66739827E−32
3.99932640E−29









Next, a zoom lens of Example 3 will be described. FIG. 3 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 3.
The zoom lens of Example 3 is constituted by, in order from the object side to the image side, a first lens group G1 having a positive refractive power as a whole constituted by twelve lenses, which are lenses L1a through L1l, a second lens group G2 having a negative refractive power as a whole constituted by five lenses, which are lenses L2a through L2e, a third lens group G3 having a negative refractive power as a whole constituted by two lenses, which are lenses L1a and L3b, and a fourth lens group G4 (final lens group) having a positive refractive power as a whole constituted by eleven lenses, which are lenses L4a through L4k.
Note that the first lens group G1 is constituted by a 1a lens group G1a constituted by five lenses, which are lenses L1a through L1e, a 1b lens group G1b constituted by three lenses, which are lenses L1f through L1h, and a 1c lens group G1c constituted by four lenses, which are lenses L1i through L1l.
In addition, basic lens data are shown in Table 9, data related to various items are shown in Table 10, data related to variable distances among surfaces are shown in Table 11, and data related to aspherical surface coefficients are shown in Table 12 for the zoom lens of Example 3. In addition, FIG. 10 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 3.







TABLE 9







Example 3: Lens Data












Surface
Radius of






Number
Curvature
Distance
nd
νd
θgF















*1
1236.5135
5.000
1.72916
54.68
0.5445


2
42.7839
23.979





*3
84.1690
2.801
1.80610
40.93
0.5702


4
49.8993
11.647





5
4813.3540
2.399
1.91082
35.25
0.5822


6
142.7582
14.043





7
−56.7466
3.110
1.53775
74.70
0.5394


8
−120.6330
4.660





9
222.3933
12.204
1.67300
38.15
0.5754


10
−99.2785
DD[10]





11
−1033.6040
4.758
1.72342
37.95
0.5837


12
−177.0679
0.199





13
−334.6268
10.065
1.59522
67.73
0.5443


14
−69.6882
3.601
1.91082
35.25
0.5822


15
−168.8087
DD[15]





16
880.6320
3.501
1.88300
40.76
0.5668


17
95.6448
15.204
1.43875
94.66
0.5340


18
−129.7957
7.394





19
3024.1495
11.220
1.43875
94.66
0.5340


20
−83.4751
0.149





21
308.9265
5.127
1.49700
81.54
0.5375


22
−423.9541
DD[22]





*23
58.0203
3.055
1.49700
81.54
0.5375


24
28.4502
18.919





25
−48.2627
1.758
1.60342
38.03
0.5836


26
−42.3506
1.309
1.60300
65.44
0.5402


27
76.7313
3.270





28
79.4705
1.299
1.80518
25.46
0.6157


29
40.6022
6.509
1.80100
34.97
0.5864


30
−164.4388
DD[30]





31
−54.3750
1.299
1.59282
68.62
0.5441


32
88.5331
3.844
1.58144
40.75
0.5776


33
−119.0663
DD[33]





34 (stop)
∞
1.726





35
111.9209
3.073
1.59522
67.73
0.5443


36
−217.3750
0.149





37
87.9338
5.334
1.80519
25.47
0.6101


38
−64.1772
1.209
1.80440
39.59
0.5730


39
1052.9687
5.177





40
49.7764
5.960
1.49700
81.54
0.5375


41
−58.7352
1.399
1.80518
25.42
0.6162


42
57.1243
19.272





43
128.3267
4.068
1.80519
25.47
0.6101


44
−63.9826
0.997





45
49.1760
6.664
1.69560
59.05
0.5435


46
−52.3643
1.209
1.88300
40.76
0.5668


47
28.3702
1.800





48
35.8189
8.102
1.49700
81.54
0.5375


49
−28.1113
6.259
1.95375
32.32
0.5901


50
99.5492
0.214





51
70.0624
13.181
1.51633
64.14
0.5353


52
−35.0814
3.000





53
∞
1.400
1.51633
64.14
0.5353


54
∞
1.000





55
∞
3.760
1.51633
64.14
0.5353


56
∞
45.281
















TABLE 10







Example 3: Items (d line)











Wide Angle
Intermediate
Telephoto















Zoom Ratio
1.00
1.90
2.94



f′
12.13
23.05
35.66



FNo.
2.86
2.86
2.86



2ω (°)
101.8
62.4
43.0
















TABLE 11







Example 3: Zoom Distances











Wide Angle
Intermediate
Telephoto















DD[10]
4.933
4.933
4.933



DD[15]
12.000
12.000
12.000



DD[22]
1.743
54.985
82.201



DD[30]
74.789
20.546
3.375



DD[33]
11.827
12.829
2.784
















TABLE 12







Example 3: Aspherical Surface Coefficients









Surface Number











1
3
23





KA
 1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−2.78396252E−06
6.71313499E−06
−1.88314377E−06 


A4
 3.36311293E−06
−3.78122473E−06 
1.64761682E−06


A5
−2.32739880E−08
7.15575727E−08
4.30350762E−09


A6
−1.04410442E−09
−2.17499598E−09 
6.22850294E−10


A7
 1.31377861E−12
−1.01246385E−11 
−7.58307093E−12 


A8
 6.77104495E−13
2.09113430E−12
−2.46725890E−12 


A9
−1.68852841E−15
−1.71185750E−15 
4.71771142E−14


A10
−2.09072620E−16
−1.38696668E−15 
9.93329520E−15


A11
 1.30347899E−19
2.39941322E−18
−1.10330478E−16 


A12
 3.16095038E−20
4.24890535E−19
−1.24689114E−17 


A13
 1.08227861E−22
2.05396121E−21
−1.43394162E−19 


A14
 1.01339127E−24
5.95050683E−23
−2.60173012E−21 


A15
−7.08453554E−27
5.04000516E−25
4.64725005E−22


A16
−3.62652371E−28
−4.16315192E−26 
9.65922716E−24


A17
−1.04199916E−29
−1.78996781E−27 
1.39494618E−24


A18
−1.59547591E−31
−4.59649816E−29 
−2.16629510E−26 


A19
−9.89068967E−34
−4.46345226E−31 
−3.23578302E−27 


A20
 7.57626524E−35
4.65621285E−32
6.62193769E−29









Next, a zoom lens of Example 4 will be described. FIG. 4 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 4.
The zoom lens of Example 4 is constituted by, in order from the object side to the image side, a first lens group G1 having a positive refractive power as a whole constituted by eleven lenses, which are lenses L1a through L1k, a second lens group G2 having a positive refractive power as a whole constituted by only one lens, which is a lens L2a, a third lens group G3 having a negative refractive power as a whole constituted by five lenses, which are lenses L3a through L3e, a fourth lens group G4 having a negative refractive power as a whole constituted by two lenses, which are lenses L4a and L4b, and a fifth lens group G5 (final lens group) having a positive refractive power as a whole constituted by eleven lenses, which are lenses L5a through L5k.
Note that the first lens group G1 is constituted by a 1a lens group G1a constituted by five lenses, which are lenses L1a through L1e, a 1b lens group G1b constituted by three lenses, which are lenses L1f through L1h, and a 1c lens group G1c constituted by three lenses, which are lenses L1i through L1k.
In addition, basic lens data are shown in Table 13, data related to various items are shown in Table 14, data related to variable distances among surfaces are shown in Table 15, and data related to aspherical surface coefficients are shown in Table 16 for the zoom lens of Example 4. In addition, FIG. 11 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 4.







TABLE 13







Example 4: Lens Data












Surface
Radius of






Number
Curvature
Distance
nd
νd
θgF















*1
611.6241
4.999
1.72916
54.68
0.5445


2
43.0090
23.977





*3
84.2654
2.801
1.72916
54.68
0.5445


4
50.2209
12.669





5
−509.3035
2.399
1.90366
31.31
0.5948


6
97.2009
16.055





7
−54.7354
2.521
1.49700
81.54
0.5375


8
−112.3395
0.762





9
256.7812
12.899
1.72047
34.71
0.5835


10
−84.7040
DD[10]





11
1394.9826
6.818
1.56732
42.82
0.5731


12
−142.1118
0.199





13
−711.9176
12.357
1.59282
68.62
0.5441


14
−61.6355
3.582
1.91082
35.25
0.5822


15
−165.2168
DD[15]





16
1745.0802
2.999
1.88300
40.76
0.5668


17
89.7471
13.863
1.43875
94.66
0.5340


18
−122.9182
12.102





19
−445.0803
11.148
1.43875
94.66
0.5340


20
−72.0979
DD[20]





21
115.1885
5.649
1.49700
81.54
0.5375


22
−443.3357
DD[22]





*23
92.2350
2.999
1.59282
68.62
0.5441


24
34.5945
10.197





25
−58.0235
2.378
1.62004
36.26
0.5880


26
−43.0353
1.309
1.61800
63.33
0.5441


27
90.8097
7.280





28
92.2231
1.299
1.80518
25.42
0.6162


29
34.2804
6.510
1.80000
29.84
0.6018


30
−507.0856
DD[30]





31
−43.9303
1.299
1.61800
63.33
0.5441


32
69.3453
4.448
1.59270
35.31
0.5934


33
−128.8295
DD[33]





34 (stop)
∞
1.983





35
156.3168
3.758
1.58913
61.13
0.5407


36
−90.2315
0.149





37
83.1206
6.943
1.80518
25.43
0.6103


38
−124.1461
2.509
1.80440
39.59
0.5730


39
−4631.7618
2.009





40
56.0963
6.093
1.49700
81.54
0.5375


41
−60.0790
1.501
1.78472
25.68
0.6162


42
57.6300
20.607





43
122.6141
4.233
1.80518
25.43
0.6103


44
−69.7199
3.553





45
47.2239
4.986
1.53775
74.70
0.5394


46
−54.5659
1.499
1.79952
42.22
0.5673


47
28.6533
1.678





48
34.5188
8.160
1.49700
81.54
0.5375


49
−30.7033
4.541
1.95375
32.32
0.5901


50
95.3450
0.150





51
61.6857
13.401
1.48749
70.24
0.5301


52
−35.7142
3.000





53
∞
1.400
1.51633
64.14
0.5353


54
∞
1.000





55
∞
3.690
1.51633
64.14
0.5353


56
∞
48.612
















TABLE 14







Example 4: Items (d line)













Wide Angle
Intermediate
Telephoto
















Zoom Ratio
1.00
1.90
2.94



f′
12.13
23.05
35.67



FNo.
2.86
2.86
2.86



2ω (°)
102.2
62.4
43.2

















TABLE 15







Example 4: Zoom Distances











Wide Angle
Intermediate
Telephoto
















DD[10]
1.504
1.504
1.504



DD[15]
8.062
8.062
8.062



DD[20]
1.709
19.242
36.117



DD[22]
0.576
30.480
44.695



DD[30]
77.744
30.703
4.460



DD[33]
7.150
6.754
1.907

















TABLE 16







Example 4: Aspherical Surface Coefficients









Surface Number











1
3
23














KA
1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−3.79267381E−06
7.77369253E−06
−2.13579459E−06


A4
3.17212640E−06
−3.95786533E−06
4.41321477E−07


A5
−2.19548887E−08
7.34888830E−08
−6.29270461E−09


A6
−1.02289636E−09
−1.88238585E−09
3.09890218E−10


A7
2.00288741E−12
−1.11706885E−11
−1.17511139E−11


A8
6.59256187E−13
2.16594773E−12
−2.39545534E−12


A9
−1.83366970E−15
−2.71954025E−15
4.90811051E−14


A10
−2.07675211E−16
−1.39995123E−15
1.01203142E−14


A11
1.41466668E−19
2.04469973E−18
−1.08677281E−16


A12
3.18013714E−20
4.25233594E−19
−1.36204236E−17


A13
1.09068072E−22
1.99172151E−21
−1.32500906E−19


A14
1.01467934E−24
5.74342767E−23
−6.11271642E−21


A15
−7.22594558E−27
6.26541679E−25
3.65500596E−22


A16
−3.65147509E−28
−3.94247984E−26
−3.41985713E−25


A17
−1.05391228E−29
−1.82458274E−27
1.81405280E−24


A18
−1.61820829E−31
−4.30897965E−29
1.71039651E−26


A19
−1.00837111E−33
−3.40391639E−31
−8.61576912E−28


A20
7.57841102E−35
4.06959794E−32
−7.72625188E−29









Next, a zoom lens of Example 5 will be described. FIG. 5 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 5. The zoom lens of Example 5 has the same number of lenses and the same lens configuration as the zoom lens of Example 4. Basic lens data are shown in Table 17, data related to various items are shown in Table 18, data related to variable distances among surfaces are shown in Table 19, and data related to aspherical surface coefficients are shown in Table 20 for the zoom lens of Example 5. In addition, FIG. 12 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 5.







TABLE 17







Example 5: Lens Data












Surface







Number
Radius of Curvature
Distance
nd
νd
θgF
















*1

666.6823
5.000
1.72916
54.68
0.5445


2

42.7467
24.024


*3

95.0754
2.799
1.80610
40.93
0.5702


4

50.5817
11.168


5

829.1279
2.400
1.91082
35.25
0.5822


6

119.1291
14.621


7

−58.2787
3.301
1.53775
74.70
0.5394


8

−116.2341
5.532


9

210.4026
12.933
1.64665
35.68
0.5858


10

−105.4508
DD[10]


11

−939.8487
5.692
1.69763
37.46
0.5826


12

−143.9374
0.201


13

−502.6960
10.617
1.59522
67.73
0.5443


14

−69.9202
3.600
1.91082
35.25
0.5822


15

−196.0975
DD[15]


16

1224.8928
3.001
1.88300
40.76
0.5668


17

96.2921
15.047
1.43875
94.66
0.5340


18

−131.1512
3.869


19

424.4044
12.001
1.43875
94.66
0.5340


20

−87.4145
DD[20]


21

352.3454
4.617
1.49700
81.54
0.5375


22

−537.5402
DD[22]


*23

54.6748
3.000
1.49700
81.54
0.5375


24

28.1791
18.042


25

−50.4191
2.754
1.60342
38.03
0.5836


26

−36.2927
1.310
1.60300
65.44
0.5402


27

70.6131
1.957


28

68.7224
1.299
1.80518
25.46
0.6157


29

36.5763
6.511
1.80100
34.97
0.5864


30

−255.7170
DD[30]


31

−48.2746
1.300
1.59282
68.62
0.5441


32

56.5754
4.468
1.58144
40.75
0.5776


33

−153.0068
DD[33]


34
(stop)
∞
2.003


35

142.5835
2.951
1.66859
58.07
0.5426


36

−135.2406
0.149


37

90.0679
4.925
1.80519
25.47
0.6101


38

−74.1510
1.211
1.80440
39.59
0.5730


39

−10057.1794
2.967


40

50.1513
6.121
1.49700
81.54
0.5375


41

−58.4119
1.400
1.78929
25.54
0.6110


42

56.7875
19.859


43

120.6065
4.146
1.80519
25.47
0.6101


44

−65.4318
0.999


45

49.6164
6.090
1.66597
58.20
0.5426


46

−53.1161
1.201
1.88300
40.76
0.5668


47

28.6534
1.735


48

35.2727
8.206
1.49700
81.54
0.5375


49

−29.0312
4.173
1.95375
32.32
0.5901


50

95.4429
0.149


51

64.7599
13.401
1.51599
64.39
0.5381


52

−35.8213
3.000


53

∞
1.400
1.51633
64.14
0.5353


54

∞
1.000


55

∞
3.760
1.51633
64.14
0.5353


56

∞
48.570
















TABLE 18







Example 5: Items (d line)











Wide Angle
Intermediate
Telephoto
















Zoom Ratio
1.00
1.90
2.94



f′
12.14
23.06
35.68



FNo.
2.86
2.86
2.86



2ω (°)
101.8
62.4
43.0

















TABLE 19







Example 5: Zoom Distances











Wide Angle
Intermediate
Telephoto
















DD[10]
8.850
8.850
8.850



DD[15]
10.294
10.294
10.294



DD[20]
3.529
4.041
8.119



DD[22]
1.035
50.393
74.166



DD[30]
75.611
25.502
3.756



DD[33]
8.036
8.275
2.170

















TABLE 20







Example 5: Aspherical Surface Coefficients









Surface Number











1
3
23














KA
1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−3.79267381E−06
7.77369253E−06
−2.13579459E−06


A4
3.08816575E−06
−3.63855252E−06
1.47163910E−06


A5
−1.60690917E−08
7.12912047E−08
1.20519166E−09


A6
−1.09429310E−09
−2.02247919E−09
6.82692882E−10


A7
1.30016770E−12
−1.12989973E−11
−1.07063651E−11


A8
6.70813102E−13
2.09891485E−12
−2.43084305E−12


A9
−1.58597109E−15
−1.93010451E−15
5.06077625E−14


A10
−2.08942542E−16
−1.38653907E−15
9.97208937E−15


A11
1.30082612E−19
2.35999931E−18
−1.07909394E−16


A12
3.16390426E−20
4.26989245E−19
−1.26730592E−17


A13
1.07537876E−22
2.02816792E−21
−1.53511762E−19


A14
1.00223404E−24
5.88331353E−23
−2.90127582E−21


A15
−7.13877311E−27
5.24336365E−25
4.91971553E−22


A16
−3.58425980E−28
−4.23519399E−26
9.57551896E−24


A17
−1.04600688E−29
−1.84128581E−27
1.21864288E−24


A18
−1.60608825E−31
−4.67174622E−29
−1.11137033E−26


A19
−9.91973045E−34
−4.54746669E−31
−3.17226066E−27


A20
7.59906780E−35
4.89125983E−32
5.67978343E−29









Next, a zoom lens of Example 6 will be described. FIG. 6 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 6. The zoom lens of Example 6 has the same number of lenses and the same lens configuration as the zoom lens of Example 4. Basic lens data are shown in Table 21, data related to various items are shown in Table 22, data related to variable distances among surfaces are shown in Table 23, and data related to aspherical surface coefficients are shown in Table 24 for the zoom lens of Example 6. In addition, FIG. 13 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 6.







TABLE 21







Example 6: Lens Data












Surface







Number
Radius of Curvature
Distance
nd
νd
θgF
















*1

720.9888
5.000
1.72916
54.68
0.5445


2

42.7441
23.981


*3

83.5774
2.799
1.72916
54.68
0.5445


4

52.5981
12.777


5

−266.3340
2.399
1.94999
26.16
0.6119


6

112.1747
15.411


7

−54.4818
2.499
1.43875
94.66
0.5340


8

−133.2456
0.401


9

290.3445
13.099
1.73800
32.26
0.5900


10

−80.2289
DD[10]


11

1465.2152
6.641
1.56732
42.82
0.5731


12

−145.8072
0.199


13

−609.3755
13.031
1.59282
68.62
0.5441


14

−58.3631
2.999
1.91082
35.25
0.5822


15

−147.7936
DD[15]


16

3821.7337
2.999
1.88300
40.76
0.5668


17

93.2323
13.639
1.43875
94.66
0.5340


18

−108.8913
15.872


19

−299.8528
9.616
1.43875
94.66
0.5340


20

−71.2398
DD[20]


21

120.0615
5.467
1.49700
81.54
0.5375


22

−451.7087
DD[22]


*23

93.5156
2.999
1.59282
68.62
0.5441


24

32.9359
10.172


25

−51.8309
1.732
1.62004
36.26
0.5880


26

−45.0164
1.310
1.61800
63.33
0.5441


27

116.5947
6.772


28

101.3784
1.299
1.80518
25.42
0.6162


29

34.9315
6.511
1.80000
29.84
0.6018


30

−257.9508
DD[30]


31

−43.7192
1.300
1.61800
63.33
0.5441


32

78.5468
4.486
1.59270
35.31
0.5934


33

−104.8622
DD[33]


34
(stop)
∞
1.866


35

141.5395
3.506
1.58913
61.13
0.5407


36

−114.6360
0.149


37

83.3614
8.900
1.80518
25.43
0.6103


38

−171.9012
2.511
1.80440
39.59
0.5730


39

−3427.6730
3.576


40

60.3173
5.901
1.49700
81.54
0.5375


41

−58.8661
1.499
1.78472
25.68
0.6162


42

59.6604
20.140


43

128.7780
4.283
1.80518
25.43
0.6103


44

−67.9375
4.037


45

51.9878
5.349
1.53775
74.70
0.5394


46

−46.1818
1.500
1.79952
42.22
0.5673


47

27.8391
1.562


48

32.1332
9.054
1.49700
81.54
0.5375


49

−28.3436
3.022
1.95375
32.32
0.5901


50

175.1794
0.623


51

80.5048
13.401
1.48749
70.24
0.5301


52

−33.5185
3.000


53

∞
1.400
1.51633
64.14
0.5353


54

∞
1.000


55

∞
3.690
1.51633
64.14
0.5353


56

∞
48.419
















TABLE 22







Example 6: Items (d line)











Wide Angle
Intermediate
Telephoto
















Zoom Ratio
1.00
1.90
2.94



f′
12.13
23.04
35.65



FNo.
2.86
2.86
2.86



2ω (°)
102.2
62.4
43.2

















TABLE 23







Example 6: Zoom Distances











Wide Angle
Intermediate
Telephoto
















DD[10]
1.505
1.505
1.505



DD[15]
7.920
7.920
7.920



DD[20]
1.676
14.922
30.572



DD[22]
0.616
33.096
48.007



DD[30]
73.706
28.864
4.272



DD[33]
8.510
7.626
1.657

















TABLE 24







Example 6: Aspherical Surface Coefficients









Surface Number











1
3
23














KA
1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−3.79267381E−06
7.77369253E−06
−2.13579459E−06


A4
3.43124383E−06
−4.31934600E−06
6.34919063E−07


A5
−2.82099665E−08
7.29270735E−08
−6.46247210E−09


A6
−9.69191271E−10
−1.90075033E−09
2.98634441E−10


A7
1.44954007E−12
−1.06709266E−11
−1.11021290E−11


A8
6.82544312E−13
2.20452609E−12
−2.36981658E−12


A9
−1.95746128E−15
−3.01462331E−15
5.22583969E−14


A10
−2.09263407E−16
−1.40430171E−15
1.01305617E−14


A11
1.33557677E−19
1.85488134E−18
−1.17022067E−16


A12
3.17782734E−20
4.22528921E−19
−1.39802644E−17


A13
1.10805778E−22
1.96374712E−21
−1.91863981E−19


A14
1.04653083E−24
5.63814969E−23
−6.29926869E−21


A15
−6.73207866E−27
6.71959911E−25
3.81827537E−22


A16
−3.59209165E−28
−3.84742212E−26
2.56475274E−24


A17
−1.04582542E−29
−1.77779559E−27
2.43128708E−24


A18
−1.61161149E−31
−4.20176418E−29
1.08598630E−26


A19
−1.00927738E−33
−3.45319852E−31
−5.52864322E−28


A20
7.56465850E−35
3.99789994E−32
−1.24533336E−28









Next, a zoom lens of Example 7 will be described. FIG. 7 is a collection of cross sectional diagrams that illustrate the lens configuration of the zoom lens of Example 7. The zoom lens of Example 7 has the same number of lenses and the same lens configuration as the zoom lens of Example 4. Basic lens data are shown in Table 25, data related to various items are shown in Table 26, data related to variable distances among surfaces are shown in Table 27, and data related to aspherical surface coefficients are shown in Table 28 for the zoom lens of Example 7. In addition, FIG. 14 is a collection of diagrams that illustrate various aberrations of the zoom lens of Example 7.







TABLE 25







Example 7: Lens Data












Surface







Number
Radius of Curvature
Distance
nd
νd
θgF
















*1

620.0124
5.001
1.72916
54.68
0.5445


2

43.1045
24.410


*3

110.7421
2.800
1.80610
40.93
0.5702


4

47.2896
15.057


5

−308.2095
2.524
1.91082
35.25
0.5822


6

221.2196
12.659


7

−62.3975
2.500
1.53775
74.70
0.5394


8

−116.9980
2.581


9

229.8331
12.373
1.72047
34.71
0.5835


10

−94.4939
DD[10]


11

645.1587
11.435
1.56732
42.82
0.5731


12

−129.4768
0.200


13

1096.1308
11.572
1.59282
68.62
0.5441


14

−69.0840
2.908
1.91082
35.25
0.5822


15

−326.8838
DD[15]


16

908.1935
2.650
1.88300
40.76
0.5668


17

83.3310
16.154
1.43875
94.66
0.5340


18

−161.0353
9.149


19

−478.9183
11.842
1.43875
94.66
0.5340


20

−72.8359
DD[20]


21

129.4863
5.514
1.49700
81.54
0.5375


22

−367.6692
DD[22]


*23

78.7279
3.000
1.59282
68.62
0.5441


24

34.3649
7.681


25

−67.3423
3.591
1.62004
36.26
0.5880


26

−41.6530
1.309
1.61800
63.33
0.5441


27

68.0011
7.457


28

75.3447
1.301
1.74077
27.79
0.6096


29

30.4950
6.500
1.73800
32.26
0.5900


30

−1340.9778
DD[30]


31

−43.0976
1.301
1.61800
63.33
0.5441


32

61.6660
4.749
1.59270
35.31
0.5934


33

−124.7213
DD[33]


34
(stop)
∞
2.131


35

181.9135
3.956
1.59522
67.73
0.5443


36

−93.4507
0.151


37

94.8331
4.558
1.80518
25.43
0.6103


38

−118.4030
1.510
1.80440
39.59
0.5730


39

−902.1238
3.814


40

51.9558
6.819
1.49700
81.54
0.5375


41

−61.8300
1.999
1.78472
25.68
0.6162


42

58.5434
19.036


43

116.6437
5.826
1.80518
25.43
0.6103


44

−70.4189
2.436


45

53.3390
5.864
1.59282
68.62
0.5441


46

−53.3390
1.495
1.83481
42.72
0.5649


47

28.9062
1.694


48

34.9661
9.693
1.49700
81.54
0.5375


49

−29.3610
2.286
1.95375
32.32
0.5901


50

124.4152
0.353


51

67.1748
13.400
1.48749
70.24
0.5301


52

−35.7166
5.000


53

∞
1.400
1.51633
64.14
0.5353


54

∞
1.000


55

∞
3.690
1.51633
64.14
0.5353


56

∞
47.645
















TABLE 26







Example 7: Items (d line)











Wide Angle
Intermediate
Telephoto
















Zoom Ratio
1.00
1.90
2.94



f′
12.12
23.03
35.63



FNo.
2.85
2.85
2.85



2ω (°)
102.0
62.6
43.2

















TABLE 27







Example 7: Zoom Distances











Wide Angle
Intermediate
Telephoto
















DD[10]
1.944
1.944
1.944



DD[15]
7.604
7.604
7.604



DD[20]
2.993
10.043
21.618



DD[22]
0.788
37.418
54.615



DD[30]
71.396
28.361
4.619



DD[33]
7.554
6.908
1.879

















TABLE 28







Example 7: Aspherical Surface Coefficients









Surface Number











1
3
23














KA
1.00000000E+00
1.00000000E+00
1.00000000E+00


A3
−3.79267381E−06
7.77369253E−06
−2.13579459E−06


A4
3.05396688E−06
−3.53726191E−06
4.67377256E−07


A5
−1.58949456E−08
7.25905827E−08
−1.03930108E−08


A6
−1.11778765E−09
−1.94634143E−09
2.33349715E−10


A7
2.88140472E−12
−1.01626981E−11
5.30322938E−12


A8
6.55805075E−13
2.17411825E−12
−1.71572287E−12


A9
−1.89633398E−15
−2.35603476E−15
1.81844609E−14


A10
−2.06015119E−16
−1.41174817E−15
8.58816477E−15


A11
1.60603752E−19
1.82716729E−18
−1.32452870E−16


A12
3.20087757E−20
4.18204047E−19
−1.30195079E−17


A13
9.54541440E−23
1.85900170E−21
−5.40768220E−20


A14
1.07311109E−24
5.35431955E−23
−4.88866480E−21


A15
−6.57878596E−27
6.68557294E−25
4.15495783E−22


A16
−3.39223115E−28
−3.57771926E−26
4.02031048E−23


A17
−1.12469968E−29
−1.78996826E−27
5.56385014E−25


A18
−1.58539863E−31
−3.93402007E−29
−2.78067849E−26


A19
−9.74722274E−34
−2.05853915E−31
−1.38439284E−27


A20
7.62412059E−35
3.69864088E−32
−2.74220828E−29









Table 29 shows values corresponding to Conditional Formulae (1) through (10) for the zoom lenses of Examples 1 through 7. Note that all of the Examples use the d line as a reference wavelength, and the values shown in Table 29 below are those for the reference wavelength.















TABLE 29







Example
Example
Example
Example
Example
Example
Example


Formula
Condition
1
2
3
4
5
6
7























(1)
νd1an
81.54
75.50
74.70
81.54
74.70
94.66
74.70


(2)
θgF1an +
0.6700
0.6627
0.6607
0.6700
0.6607
0.6878
0.6607



0.001625 ×



νd1an


(3)
f1an/f1a
4.916
5.577
4.032
4.721
4.678
4.621
5.253


(4)
f1c/fw
10.563
11.132
9.901
17.462
14.052
17.676
20.397


(5)
νd1ap
34.71
32.26
38.15
34.71
35.68
32.26
34.71


(6)
θgF1ap +
0.6399
0.6424
0.6374
0.6399
0.6438
0.6424
0.6399



0.001625 ×



νd1ap


(7)
f1ap/f1
1.222
1.312
0.859
0.682
1.234
0.656
0.596


(8)
DL3/DL2
—
—
—
2.283
16.917
2.640
3.639


(9)
f3/f4
—
—
—
0.601
0.643
0.545
0.627


(10) 
νd3p − νd3n
—
—
—
4.42
9.51
4.42
4.47









As can be understood from the above data, all of the zoom lenses of Examples 1 through 7 satisfy Conditional Formulae (1) through (10), and are compact zoom lenses with the values of total length/image size being 35 or less, have wide angles of view with the values of the half angle of view at the wide angle end being 40 degrees or greater, and also have high performance with various aberrations being favorably corrected.
Next, an imaging apparatus according to an embodiment of the present disclosure will be described. FIG. 15 is a diagram that illustrates the schematic structure an imaging apparatus that employs a zoom lens according to an embodiment of the present disclosure as an example of an imaging apparatus of the present disclosure. Note that each of the lens groups is schematically illustrated in FIG. 15. The imaging apparatus may be a video camera, a digital still camera, or the like which is equipped with a solid state imaging element such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor), for example.
The imaging apparatus 10 illustrated in FIG. 15 is equipped with a zoom lens 1, a filter 6 that functions as a low pass filter or the like, provided at the image side of the zoom lens 1, an imaging element 7 provided at the image side of the filter 6, and a signal processing circuit 8. The imaging element 7 converts optical images formed by the zoom lens 1 into electrical signals. A CCD, a CMOS, or the like may be employed as the imaging element 7. The imaging element 7 is provided such that the image capturing surface thereof matches the image formation plane of the zoom lens 1.
Images obtained through the zoom lens 1 are formed on the image capturing surface of the imaging element 7. Output signals related to these images are processed by the signal processing circuit 8, and the images are displayed by a display device 9.
The imaging apparatus 10 of the present embodiment is equipped with the zoom lens 1 of the present disclosure. Therefore, the imaging apparatus 10 is capable of obtaining wide angle images having high image quality.
The present disclosure has been described with reference to the embodiments and Examples. However, the present disclosure is not limited to the above embodiments and Examples, and various modifications are possible. For example, the numerical values of the radii of curvature, the distances among surfaces, the refractive indices, the Abbe's numbers, etc. of the lens components are not limited to those exemplified in the above Examples, and may be different values.

## Claims

1. A zoom lens comprising, in order from the object side to the image side:
a first lens group having a positive refractive power, which is fixed when changing magnification;
at least two moving lens groups that move to change the distance among adjacent lens groups in the direction of the optical axis when changing magnification; and
a final lens group having a positive refractive power, which is fixed when changing magnification;
the first lens group consisting of, in order from the object side to the image side: a 1a lens group having a negative refractive power which is fixed during focusing operations; a 1b lens group having a positive refractive power which moves during focusing operations; and a 1c lens group having a positive refractive power which is fixed during focusing operations; and
the 1a lens group including at least one negative lens that satisfies Conditional Formulae (1), (2), and (3) below


62<νd1an  (1)



0.65<θgF1an+0.001625·νd1an<0.7  (2)



3<f1an/f1a<7  (3)


wherein νd1 an is the Abbe's number with respect to the d line of the negative lens within the 1a lens group, θgF1 an is the partial dispersion of the negative lens within the 1a lens group, f1an is the focal length with respect to the d line of the negative lens within the 1a lens group, and f1a is the focal length with respect to the d line of the 1a lens group.

2. A zoom lens as defined in claim 1, in which Conditional Formula (4) below is satisfied:


8<f1c/fw<24  (4)

wherein f1c is the focal length with respect to the d line of the 1c lens group, and fw is the focal length with respect to the d line of the entire lens system at the wide angle end.

3. A zoom lens as defined in claim 2, in which Conditional Formula (4-1) below is satisfied:


9<f1c/fw<21  (4-1).

4. A zoom lens as defined in claim 1, wherein:
the 1a lens group includes at least one positive lens that satisfies Conditional Formulae (5), (6), and (7) below:


νd1ap<40  (5)



0.62<θgF1ap+0.001625·νd1ap<0.67  (6)



0.4<f1ap/f1<2  (7)


wherein νd1ap is the Abbe's number with respect to the d line of the positive lens within the 1a lens group, θgF1ap is the partial dispersion of the positive lens within the 1a lens group, f1ap is the focal length with respect to the d line of the positive lens within the 1a lens group, and f1 is the focal length with respect to the d line of the first lens group.

5. A zoom lens as defined in claim 4, in which at least one of Conditional Formulae (5-1), (6-1), and (7-1) below is satisfied:


20<νd1ap<39  (5-1)



0.63<θgF1ap+0.001625·νd1ap<0.66  (6-1)



0.5<f1ap/f1<1.5  (7-1).

6. A zoom lens as defined in claim 1, wherein:
the at least two moving lens groups consist of, in order from the object side to the image side, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power.

7. A zoom lens as defined in claim 1, wherein:
the at least two moving lens groups consist of, in order from the object side to the image side, a second lens group having a negative refractive power, and a third lens group having a negative refractive power.

8. A zoom lens as defined in claim 1, wherein:
the at least two moving lens groups consist of, in order from the object side to the image side, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a negative refractive power; and
Conditional Formula (8) below is satisfied:


1.7<DL3/DL2<20  (8)


wherein DL3 is the range of movement of the third lens group, and DL2 is the range of movement of the second lens group.

9. A zoom lens as defined in claim 8, in which Conditional Formula (9) below is satisfied:


0.4<f3/f4<0.8  (9)

wherein f3 is the focal length with respect to the d line of the third lens group, and f4 is the focal length with respect to the d line of the fourth lens group.

10. A zoom lens as defined in claim 9, in which Conditional Formula (9-1) below is satisfied:


0.5<f3/f4<0.7  (9-1).

11. A zoom lens as defined in claim 8, wherein:
the third lens group has two cemented lenses;
at least one of the cemented lenses consists of a positive lens and a negative lens; and
Conditional Formula (10) below is satisfied:


0<νd3p−νd3n<10  (10)


wherein νd3p is the Abbe's number with respect to the d line of the positive lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group, and νd3n is the Abbe's number with respect to the d line of the negative lens of the cemented lens consisting of a positive lens and a negative lens within the third lens group.

12. A zoom lens as defined in claim 11, wherein:
a cemented lens provided most toward the image side within the third lens group satisfies Conditional Formula (10).

13. A zoom lens as defined in claim 11, in which Conditional Formula (10-1) below is satisfied:


4<νd3p−νd3n<10  (10-1).

14. A zoom lens as defined in claim 8, in which Conditional Formula (8-1) below is satisfied:


2.1<DL3/DL2<17  (8-1).

15. A zoom lens as defined in claim 1, in which at least one of Conditional Formulae (1-1), (2-1), and (3-1) is satisfied:


70<νd1an<100  (1-1)



0.66<θgF1an+0.001625·νd1an<0.69  (2-1)



4<f1an/f1a<6  (3-1).

16. An imaging apparatus equipped with a zoom lens as defined in claim 1.